1. Field of the Invention
This invention pertains generally to the field of inflatable mattresses and more particularly is directed to an air support bed of modular construction in which air distribution conduits supplying multiple inflatable chambers are integrated into a common base pad to dispense with external air hoses.
2. State of the Prior Art
Air support beds are in widespread use in medical care settings, particularly for patients requiring long term bed care. Bed ridden patients are susceptible to skin ulcerations caused by excessive buildup of heat and moisture on the skin, typically in combination with pressure, friction and shear forces exerted on the skin by contact with the bed surface, which tend to close off capillary blood circulation in skin tissues. Such ulcerations are painful and slow to heal, and are a frequent complication in bed ridden individuals. Air mattresses and air support beds have been found to alleviate this problem because the air filled chambers of the bed tend to conform to the anatomy of the bed ridden patient better than ordinary mattresses and consequently distribute pressure over a wider area of skin, thereby diminishing the risk and severity of skin ulcerations. Furthermore, the firmness of an air mattress can be controlled and adjusted simply by increasing or diminishing the internal air pressure, and air support beds featuring positive pressure regulation by means of electronically controlled air pumps have been developed. Air mattresses with compartmentalized air chambers which can be individually pressurized to different degrees are used for creating different zones of varying firmness adapted to the requirements of different anatomical areas of the patient's anatomy.
The requirements of long term medical bed care has led to the development of four principal classes of air beds.
Static pressure air beds are kept inflated to a preset pressure by an air blower or air pump.
Computerized or positive pressure control air beds feature one or more air pressure sensors connected to an electronic control system which actuates an air pump and an air relief valve, supplying or venting compressed air as needed to hold the internal pressure of the air chambers of the bed at a preset level, compensating as the user shift positions or gets in and out of the bed.
Cyclic pressure air beds alternately inflate and deflate different air chambers of the bed mattress so as to periodically shift pressure between different areas of the user's anatomy. The cyclic action of the air bed tends to stimulate the affected tissues and provides an opportunity for blood circulation to re-establish itself in those areas.
Low loss air beds have air chambers with finely perforated walls which allow pressurized air to leak continuously from the air chambers at a controlled rate into the bed cavity containing the air support unit. The continuous airflow under the patient carries away excess moisture and prevents heat buildup, which as earlier mentioned are among the principal causes of skin tissue breakdown in bed ridden patients.
Each of these categories of air beds has its particular advantages, and one type may be preferred over the others depending on a combination of medical benefit and economic considerations.
Existing air beds of these different types make use of external conduits, typically plastic hoses, connected in a manifold arrangement for distributing pressurized air from a common source, such as an electric air pump, to each of the inflatable elements of the air bed. The external air hoses usually include a main conduit connected at one end to the air pump and running the length of the air mattress along one side, with branch tubes feeding each inflatable element of the mattress. This air hose manifold is a relatively costly and complex component of the air bed. It is awkward to handle and detracts from the visual appearance of the air bed, and is normally tucked away out of sight between the air matress and the bed frame.
What is needed is a multichamber air bed with an integral air distribution system which eliminates the need for the external air hose manifold. The improved air bed should be of reduced complexity and cost competitive with conventional air beds.